flecainide acetate: clinical use

Prescribing considerations

• Initiate under hospital or specialist supervision.
• Exclude structural heart disease or impaired left ventricular function where required by the licensed indication.
• Correct electrolyte disturbances before treatment.
• Use caution in renal or significant hepatic impairment, older people and patients with pacemakers.
• Treat formulation switching as clinically significant.
• Consider accompanying AV-nodal blockade where clinically appropriate because atrial flutter may conduct rapidly to the ventricles.

Contraindications and cautions

• Hypersensitivity to flecainide or relevant excipients
• Cardiac failure, cardiogenic shock or significantly impaired ventricular function as specified by the product
• History of myocardial infarction with specified asymptomatic ventricular arrhythmias
• Long-standing atrial fibrillation where conversion to sinus rhythm has not been attempted
• Haemodynamically significant valvular heart disease
• Known Brugada syndrome
• Sinus-node dysfunction or significant conduction block without pacing rescue
• Concomitant class I anti-arrhythmic treatment where contraindicated by the product

Monitoring

• ECG before and during treatment, particularly after initiation, treatment changes or formulation switches
• Renal and hepatic function
• Potassium and other clinically relevant electrolytes
• Plasma concentrations where clearance may be reduced, interacting treatment is present or toxicity is suspected
• Pacemaker capture thresholds
• Evidence of pro-arrhythmia, heart failure, lung toxicity, hepatic dysfunction or blood dyscrasia

Clinical pharmacology

A class IC anti-arrhythmic with marked fast sodium-channel blockade and slow channel-binding kinetics. It slows conduction, prolongs PR and widens QRS, and has a modest negative inotropic effect. It is substantially metabolised through CYP2D6 and partly eliminated unchanged in urine.

Formulation and product differences

• Tablets and oral solutions are not automatically interchangeable.
• One oral solution is strawberry-flavoured, contains liquid maltitol and includes a graduated cup.
• Another is cherry-flavoured, contains sodium benzoate and includes a bottle adaptor and graduated oral syringe.
• Liquid formulations may temporarily numb the mouth.
• Check product-specific storage, in-use shelf life, excipients and measuring instructions before supply or switching.

Oral solution

Route: Oral

Strengths: 25 mg/5 mL, 50 mg/5 mL

Tablet

Route: Oral

Strengths: 50 mg, 100 mg